Enhanced sound focusing with single-slit lens

Sound transmission efficiency and beaming capability are the most important considerations in the design of single-slit lens toward high-performance acoustic imaging and detection. Here, we demonstrated numerically and experimentally enhanced sound focusing through a single subwavelength slit surrounded by grooves on both surfaces. A microscopic coupled-wave model was employed to optimize the slit-groove structure for both transmission enhancement and beam focusing. The simulated and measured results were in good agreement and readily verified the effectiveness of the proposed method in enhancing sound focusing with a single-slit lens. This work paves an alternative avenue for the design of single-slit lens, which may find potential applications in the broad field of acoustics, such as tumor boundary treatment, edge detection, and subwavelength acousto-optic modulation.